With the success of my first fly cutter, I proceeded to make another one. This one would be smaller and sized to fit 10mm (3/8") HSS tooling. Rummaging through my pile of junk, I found this old cut off stub axle. It looked like there might be a fly cutter inside. https://pic8.co/sh/BnRYlr.jpg The majority of the form was turned down and partially parted on the lathe. I finished the cut on the bandsaw as my parting tool was chattering a lot and parting makes me nervous. https://pic8.co/sh/oTXfB9.jpg The blank was then reversed in the chuck and the end faced off to complete the turning operation. https://pic8.co/sh/zE34p9.jpg Mill setup was similar to my first fly cutter. This time at 15 degrees (not sure if this is good or bad, but seems to be what the ones you can buy are). My son made his first cut on the mill, he dialed in the depth of cut, turned on the spindle and activated the power feed all by himself (under close instruction, because he's 5). https://pic8.co/sh/j4jSLX.jpg After the slot was milled, I spot faced the hole locations with a 6mm end mill. To determine the locations, I used a bit of trig., which I slightly fucked up, but not to any consequence. Given that the slot was 10mm deep (with the hole in the middle, i.e. 5mm in), at a 15 degree angle, the x location of the middle hole should have been 5 / cos(15) = 5.17mm from the angled edge. I messed up and did 5 x cos(15) = 4.83mm. Error was <0.5mm, but something to note in the future if a situation where it matters more arises. To determine the x offsets for the holes either side, that was a simple 10 x sin(15) = 2.588mm, where 10mm is the distance between the holes. https://pic8.co/sh/oKbw8J.jpg The holes were all faced, then using the DRO to get back to the same spot, they were drilled and tapped to M6. https://pic8.co/sh/mCfuOc.jpg Job done. https://pic8.co/sh/y4rgOV.jpg ---- Bonus dog photos. "look at the fly cutter" https://pic8.co/sh/9cQEi3.jpg "be a good dog" https://pic8.co/sh/ckSUSA.jpg "there's a possum over there!" (there was a possum over there) https://pic8.co/sh/lijQ7l.jpg